1. Field of the Invention
This invention relates to a resonant inverter apparatus or a resonant power converter for changing DC power into AC power, and feeding the AC power to an AC-powered load to drive the latter. Examples of the AC-powered load are an AC motor and an AC rotating machine.
2. Description of the Related Art
In general, an inverter apparatus or a power converter is provided between a DC power supply and an AC-powered load. The inverter apparatus receives DC power from the DC power supply. The inverter apparatus changes the DC power into AC power. The inverter apparatus feeds the AC power to the AC-powered load, and thereby drives the AC-powered load.
There is a power converter of an all resonant type in which resonance is always implemented by a resonant circuit. Since resonance is always implemented, such a power converter tends to encounter the problem of a great conduction loss caused in a reactor for resonance.
A power converter of a quasi resonant type solves the above-indicated problem in the power converter of the all resonant type. In the power converter of the partial resonant type, resonance is implemented only at switching moments.
U.S. Pat. No. 5,047,913 discloses a power converter of the quasi resonant type. The power converter in U.S. Pat. No. 5,047,913 has a large number of parts, and thus tends to be complicated in structure.